Systems and methods of monitoring a thermal protection system

Abstract

A method of monitoring a thermal protection system coupled to a structural component is provided. The thermal protection system includes a thermally insulative body and at least one layer of thermochromatic material applied thereon such that the at least one layer is positioned between the thermally insulative body and the structural component. The method includes determining a value of a thermochromatic property of the at least one layer of thermochromatic material, wherein the value of the thermochromatic property is responsive to an amount of heat applied to the at least one layer of thermochromatic material, comparing the value to a baseline value of the thermochromatic property, and determining degradation of the thermal protection system when the value of the thermochromatic property deviates from the baseline value.

What is claimed is: 
     
       1. A method of monitoring a thermal protection system, the method comprising:
 accessing the thermal protection system coupled to a structural component, the thermal protection system including a thermally insulative body and at least one layer of thermochromatic material applied thereon, wherein the at least one layer is positioned between the thermally insulative body and the structural component; 
 determining a value of a thermochromatic property of the at least one layer of thermochromatic material, wherein the value of the thermochromatic property includes at least one of an intensity or a frequency of light emitted from the at least one layer of thermochromatic material when exposed to non-visible light and is responsive to an amount of heat applied to the at least one layer of thermochromatic material, wherein the value of the thermochromatic property irreversibly changes based on the amount of heat applied; 
 comparing the value to a baseline value of the thermochromatic property; and 
 determining degradation of the thermal protection system when the value of the thermochromatic property deviates from the baseline value. 
 
     
     
       2. The method in accordance with  claim 1 , wherein determining a value comprises determining a plurality of values of the thermochromatic property, each of the plurality of values corresponding to a predetermined region of the at least one layer of thermochromatic material. 
     
     
       3. The method in accordance with  claim 1  further comprising directing non-visible light towards the at least one layer of thermochromatic material, wherein the thermochromatic material includes photoluminescent material configured to be activated by the non-visible light. 
     
     
       4. The method in accordance with  claim 3  further comprising at least partially removing the thermal protection system from the structural component to expose the at least one layer of thermochromatic material to the non-visible light. 
     
     
       5. The method in accordance with  claim 1 , wherein comparing the value comprises selecting the baseline value that corresponds to a temperature of the at least one layer below a predetermined threshold. 
     
     
       6. The method in accordance with  claim 1  further comprising coupling the thermal protection system to the structural component. 
     
     
       7. The method in accordance with  claim 1  further comprising coupling the thermal protection system to the structural component, the thermal protection system including the thermally insulative body that is fabricated from a plurality of heat-resistant fibers. 
     
     
       8. The method in accordance with  claim 1  further comprising coupling the thermal protection system to the structural component, the thermal protection system including the thermally insulative body that is a woven or non-woven material formed of a plurality of heat-resistant fibers. 
     
     
       9. The method in accordance with  claim 1  further comprising coupling the thermal protection system to the structural component, the thermal protection system including the thermochromatic material that is fabricated from one or more thermochromatic dyes responsive to temperatures above a predetermined threshold. 
     
     
       10. The method in accordance with  claim 1  further comprising coupling the thermal protection system to the structural component, the thermal protection system including the at least one layer of thermochromatic material with a photoluminescent material. 
     
     
       11. The method in accordance with  claim 1  further comprising coupling the thermal protection system to the structural component, the thermal protection system including the at least one layer of thermochromatic material with a plurality of portions each of which is applied to a predetermined region of the thermally insulative body. 
     
     
       12. The method in accordance with  claim 1 , wherein the thermally insulative body includes a first surface and a second surface, and the at least one layer of thermochromatic material is applied to the second surface, and
 wherein the method further comprises exposing the structural component with the thermal protection system to a first amount of heat, the thermally insulative body inhibiting heat transfer through the thermally insulative body from the first surface to the second surface so that only a second amount of heat reaches the second surface and thereby the at least one layer of thermochromatic material. 
 
     
     
       13. The method in accordance with  claim 1  further comprising:
 at least partially removing the thermal protection system from the structural component; and 
 directing non-visible light towards the at least one layer of thermochromatic material that includes a photoluminescent material that is activated by the non-visible light. 
 
     
     
       14. The method in accordance with  claim 1 , wherein determining the value of the thermochromatic property includes determining the value that is modified to a first level when a temperature of the at least one layer thermochromatic material is greater than a first predetermined threshold. 
     
     
       15. The method in accordance with  claim 14 , wherein determining the value of the thermochromatic property includes determining the value that remains at the first level when the temperature of the at least one layer thermochromatic material reduces to below the first predetermined threshold. 
     
     
       16. The method in accordance with  claim 14 , wherein determining the value of the thermochromatic property includes determining the value that is permanently modified to a second level as the temperature of the at least one layer thermochromatic material progressively increases above a second predetermined threshold. 
     
     
       17. The method in accordance with  claim 1 , wherein determining the value of the thermochromatic property includes determining the value that is substantially uniform across the at least one layer thermochromatic material when the temperature of the at least one layer is less than a predetermined threshold. 
     
     
       18. The method in accordance with  claim 1 , wherein determining the value of the thermochromatic property includes determining the value that irreversibly changes a plurality of different levels as a temperature of the at least one layer of thermochromatic material progressively increases above a predetermined threshold so that an amount of heat that reaches the at least one layer of thermochromatic material is determined based on which of the plurality of different levels the value has reached. 
     
     
       19. The method in accordance with  claim 1 , wherein determining the value of the thermochromatic property includes determining the value of the thermochromatic property that is only visible to a human eye when activated by non-visible light. 
     
     
       20. The method in accordance with  claim 1 , wherein the value of the thermochromatic property indicates the amount of heat applied to the at least one layer of thermochromatic material, and
 wherein determining the degradation of the thermal protection system includes determining the degradation that is directly proportional to the amount of heat.